Detection of the sinus node artery using electron beam computed tomography of the heart

Anatomical investigation of the sinus node artery using dual-source computed tomography

BACKGROUND

Few investigators have studied the anatomy of the sinus node artery (SNA) using noninvasive imaging modalities, so the objective of this study was to visualize the in-vivo 3-dimensional anatomical relations of the SNA using dual-source computed tomography (DSCT).

METHODS AND RESULTS

In the 101 patients included in this study, the visualization rate, anatomical type and diameter of the SNA, the distance between the orifice and coronary artery, and the terminal type of SNA were recorded. The visualization rate was 95.2% (96/101). Of 96 patients, 106 SNAs were detected among which 51 (48.1%, 51/106) originated from the right coronary artery, 52 (49.1%, 52/106) from the left circumflex artery, and 3 (2.7%, 3/106) from other branches. There were 3 types of SNA: right (n = 52), left (n = 45), and posterior (n = 9). The distance between the orifice of the right SNA and the right coronary sinus was 14.2+/-15.2 mm, for the left SNA it was 5.5+/-3.5 mm, and for the posterior SNA, 33.7+/-12.8 mm. The average diameter was 1.27+/-0.29 mm. The SNA approached the nodal tissue by 1 of 3 routes: retrocaval (51.5%), precaval (25.2%), or pericaval (22.3%).

CONCLUSION

The SNA can be visualized in vivo using DSCT, which is important for preoperative knowledge of its origin, course, termination, and anatomical type.

MDCT of the S-shaped sinoatrial node artery

OBJECTIVE

The purpose of this study was to use 64-MDCT to investigate the anatomic characteristics of the S-shaped variant of the sinoatrial node (SAN) artery and to describe the clinical implications of the findings in ablative procedures involving the left atrium.

MATERIALS AND METHODS

Coronary CT angiograms of 250 patients (152 men, 98 women; mean age, 60 +/- 12 [SD] years) were retrospectively analyzed for identification of the origin, number, anatomic course, mode of termination, and S-shaped variant of the SAN artery.

RESULTS

At least one SAN artery was detected in 244 patients. The S-shaped variant was seen in 35 (14.3%) of these patients. Thirty-four of the variants (30.6% of all left SAN arteries) arose from the proximal to middle portion of the left circumflex artery (mean distance between the ostium of the left circumflex artery and the origin of S-shaped variant, 28.7 +/- 13.1 mm). The other variant (0.7% of all right SAN arteries) originated from the distal right coronary artery. The S-shaped variant was the only artery supplying the SAN in 28 (11.4%) of the patients. In patients with two arteries supplying the SAN, the right SAN artery and the S-shaped variant of the left SAN artery were seen together in seven patients. The S-shaped SAN artery (mean distance from atrial wall, 2.43 +/- 0.992 mm) had a predictable proximal course, lying in the posterior aspect in a groove between the orifices of the left superior pulmonary vein and the left atrial appendage close to the left atrial wall. The terminal segment of the artery approached the nodal tissue posterior to the superior vena cava in 22 patients, anterior to the vena cava in 10 patients, and through branches surrounding the vena cava in two patients.

CONCLUSION

The S-shaped variation of the SAN artery is common and has a characteristic anatomic course. MDCT can be used to plan surgical and catheter-based left atrial interventions in which this artery is at risk of injury.